Rh disease occurs when an Rh-negative mother carries an Rh-positive baby. If the baby's blood cells enter the mother's bloodstream, her immune system may produce antibodies against the Rh factor, which can harm the baby in future pregnancies. This condition can lead to hemolytic disease of the newborn, where the mother's antibodies attack the baby's red blood cells, causing anemia and other complications. To prevent this, Rh-negative mothers are often given an injection of Rho(D) immune globulin during pregnancy and after delivery to block antibody production.